A normal map is a texture used in 3D graphics to simulate detailed surface features on a model without increasing its polygon count. It contains information about the surface normals, which helps create the illusion of depth and complexity by altering how light interacts with the surface. This technique is widely used in video games and animations to enhance visual realism. Normal maps are typically created from high-resolution models and applied to lower-resolution ones. They are often stored in a specific format that encodes the normal direction using RGB values, where each color channel represents a different axis. This allows for efficient rendering while maintaining detailed appearances.